Nathan Hill's debut novel The Nix (Knopf, $29.95) roils with the energy of political protest, from the streets of 1968 Chicago to Occupy Wall Street in 2011. But this isn't a book about elections, and its central rebellions are more personal and existential than ideological.

In detailing the fraught relationship between a woman accused of hurling rocks at a presidential candidate and the adult son she abandoned years earlier, Hill has produced a big, generous novel fueled by themes more universal than political belief. Regret and forgiveness haunt The Nix, even when it gets so laugh-out-loud funny that reading it in public becomes risky.

The Nix, by Nathan Hill

(Knopf)

Hill's affection for Samuel Andresen-Anderson and his estranged mom, Faye, grows more palpable when their life choices seem less than palatable.

"I started it as a political novel, but then the more I researched it I fell in love with the characters," Hill said at BookExpo America in the spring, where the book, which will be released Tuesday, was one of the most talked-about fall releases. "I felt like I didn't have the authority to say what the '60s meant, but I could tell this story and use the era as a backdrop. That became more interesting to me than making a political point."

Samuel is a failed writer and apathetic literature professor who might have stepped from the pages of Jonathan Franzen. The book's first showstopping section comes when he interrogates an ambitious but inept undergraduate about her plagiarism of a Hamlet essay. But Samuel's heart isn't really in the verbal combat, even if Hill's is. The prof is more comfortable receding into the world of Elfquest, an online fantasy role-playing game.

Wallowing in his disappointment, Samuel receives a jolt when the news shows an apparently unhinged woman throwing rocks at right-wing Wyoming Gov. Sheldon Packer. The Packer Attacker, as the media quickly dubs her, turns out to be Samuel's long-estranged mother. Samuel, facing a lawsuit over the long-overdue manuscript of his first book, is pressured into writing a tell-all.

Thus begins a sprawling tale that layers past (1968 and 1988) and present, encompassing multiple lost love affairs, the '60s student movement, the shackles of small-town ennui, classical music, online gaming, academic bureaucracy and a fateful trip to Norway. The Nix contains multitudes, but all strands lead back to a son's crushing love for his mother and the resentment he's harbored since she skipped town.

Faye isn't easily likable, especially as viewed through Samuel's wounded eyes. But there's a thrill in watching her become more human as the novel progresses.

"I didn't want her to be the bad guy, even though she very much is at the beginning," says Hill, 40. "I'm hoping the reader, like Samuel, can eventually find some tenderness for her."

Indeed, The Nix's deftest maneuver is the shift in focus, from Samuel to Faye, for long chunks of the novel's 625 pages. She emerges as a woman who faced a fork in the road, between freedom and stability, and never grew comfortable with her chosen path. In this sense she speaks for anyone who has ever looked back with regret and wondered, "What if?"

"I think it's an extreme version of something that a lot of people feel," Hill says. "I have this life that's happening to me every day, but it's maybe not exactly what I thought my life would be. We're sort of haunted by choices we didn't make or did make along the way. Sometimes those imaginary lives can be a burden."

Hill is quick to point out that his mother didn't abandon him: "I gave Faye roughly the same biography as my mom, but my mom is a wonderful, very present person," he says. Still, there's been a little tension. With all the advance buzz heaped upon The Nix, including a coveted place on the BookExpo editors buzz panel and a starred review from Kirkus, it seems a lot of readers got their hands on advance copies before the author's mother. (She wanted a hardback, not a galley, and so had to wait).

"I had to warn her that some of it will seem really familiar," Hill says. "Faye is definitely not her, but I used parts of her story whenever I needed a mom detail."

She should be pleased when her copy arrives. The Nix will go down as one of the best debut books of the year.